Memory Model = Instruction Reordering + Store Atomicity
Proceedings of the 33rd annual international symposium on Computer Architecture
Verification of causality requirements in Java memory model is undecidable
PPAM'09 Proceedings of the 8th international conference on Parallel processing and applied mathematics: Part II
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We view shared memories as structures, which define relations over the set of programs and their executions. An implementation is modeled by a transducer, where the relation it realizes is its language. This approach allows us to cast shared memory verification as language inclusion. We show that a specification can be approximated by an infinite hierarchy of finite-state transducers, called the memory model machines. Also, checking whether an execution is generated by a sequentially consistent memory is approached through a constraint satisfaction formulation. It is proved that if a memory implementation generates a non interleaved sequential and unambiguous execution, it necessarily generates one such execution of bounded size. Our paper summarizes the key results from the first author's dissertation, and may help a practitioner understand with clarity what "sequential consistency checking is undecidable" means.